Accelerated CO2 capture with controllable mineralisation via reactive bubble formation

Abstract

Carbon Capture and Utilisation (CCU) is crucial for mitigating greenhouse gas emissions from coal-fired power plants. This study presents a bubble reactor system using sodium carbonate (Na₂CO₃) and frothing reagents to improve both efficiency and sustainability. Various glycol-based polymers, along with an alcohol-based surfactant widely used in the mining and minerals industry, were evaluated for their effects on carbon dioxide (CO₂) bubble size and removal efficiency. The results demonstrate that the frothing reagents not only reduced bubble size but also increased foam layer thickness, significantly improving CO₂ removal efficiency. The thicker foam layer associated with the glycol-type polymers generates a larger interfacial area and longer gas residence time, accounting for the differences in CO₂ removal efficiency. Furthermore, after removing CO₂, the captured CO₂ was mineralised into calcium carbonate (CaCO₃). Notably, the calcium carbonate existed predominantly in the form of vaterite and the abundance and morphology of vaterite changed with adding one of the polymers into the CO₂-loaded Na₂CO₃ solution. This paper underscores the potential for scalable, sustainable CCU, along with the formation of valuable by-products.